Lubricants With Improved Seal Compatibility

ABSTRACT

The present invention relates to lubricating compositions and particularly gear oil compositions that include a minimum level of a specific antioxidant component, where the antioxidant component includes (i) a phenolic antioxidant, (ii) an aminic antioxidant, or (iii) a combination thereof, where the antioxidant component is present in the lubricating composition at from 1.0 percent by weight or higher. Such compositions provide surprisingly good seal compatibility.

FIELD OF THE INVENTION

The present invention relates to lubricating compositions andparticularly gear oil compositions that include a minimum level of aspecific antioxidant component, where the antioxidant component includes(i) a phenolic antioxidant, (ii) an aminic antioxidant, or (iii) acombination thereof, where the antioxidant component is present in thelubricating composition at 1.0 percent by weight or higher. Suchcompositions provide surprisingly good seal compatibility compared tocompositions with other triazoles and/or alternative additives.

BACKGROUND OF THE INVENTION

In many industrial applications lubricating compositions come intocontact with seals within the equipment in which they are used. Sealsare made out of various materials, including nitrile-butadiene rubber(NBR) due to its relatively low cost and high availability, as well asfluorinated elastomers, silicones, and polycarbonates. It is essentialthat the lubricating composition used has good compatibility with theseals otherwise seals are degraded over time to the point that theyfail, leading to fluid leakage increasing maintenance costs, longer downtime for the equipment, and even the risk of equipment damage.

Seals, particularly those made using NBR, break down over time undereven normal operating conditions. High temperatures in particular can bevery detrimental to some seals. In other cases seals can sometimes besusceptible to attack by chemical additive components of somelubricating compositions, including those used frequently in industrialapplications, including some extreme-pressure agents like sulfurizedolefins, rust inhibitors like aminic compounds, antiwear agents likephosphates, phosphites, phosphate esters, and phosphate amine salts. Insome cases even the base oil itself can attack seal materials includingNBR.

There is an on-going need for industrial lubricating compositions thatcan provide the required performance and protection for the equipment,but which also protect the seals attack or degradation thus reducing therisk of lubricant leakage, down time and ultimately equipment damage orfailure.

Wind turbines in particular represent an industrial application thatrequires lubricating compositions with good seal compatibility. Windturbines as an alternative renewable energy source are attracting moreinterest, since they produce electricity by converting clean wind energyto electrical energy. A gear box, which is typically situated betweenthe rotor of the wind turbine and the generator, requires a lubricant.The high torque puts a large amount of stress on the gears and bearingsin the gear box of these wind turbines, placing high performancerequirements on the lubricating composition. In addition, the gear boxesare located in nacelles of the wind turbine high off the ground and theunit themselves are often in remote areas. Thus the gear boxes are ofteninaccessible or only accessible with great cost and difficulty such thata long service life with limited maintenance is desired. Lubricatingcompositions with improved seal compatibility but which still providegood lubricating performance are expected to reduce maintenance and downtime caused by failed seals. Thus there is a need for lubricatingcompositions with improved seal compatibility, that still provide goodlubricating performance in wind turbines and similar applications.

SUMMARY OF THE INVENTION

The invention provides an industrial lubricating composition comprisingan oil of lubricating viscosity and an antioxidant component comprising:(i) a phenolic antioxidant, (ii) an aminic antioxidant, or (iii) acombination thereof where the antioxidant component is present in thelubricating composition at 0.4 percent by weight or higher, and in otherembodiments at 1.0 percent by weight or higher,

The phenolic antioxidant may be present in the lubricating compositionfrom at least 0.2, 0.4, 0.5 or at least 1.0 percent by weight and theaminic antioxidant may be present in the lubricating composition from atleast 0.2, 0.4, 0.5 or at least 1.0 percent by weight.

The invention provides for the described compositions where the oil oflubricating viscosity includes a mineral base oil, where the oil oflubricating viscosity includes a synthetic base oil, and even where theoil of lubricating viscosity includes a combination of a mineral baseoil and a synthetic base oil. In some embodiments the oil of lubricatingviscosity is substantially free of, or even free of, a synthetic esterbase oil.

The invention provides a method of lubricating a gear assemblycomprising supplying to said assembly a lubricating compositioncomprising an oil of lubricating viscosity and an antioxidant componentcomprising: (i) a phenolic antioxidant, (ii) an aminic antioxidant, or(iii) a combination thereof where the antioxidant component is presentin the lubricating composition at 0.4, 0.5 or 1.0 percent by weight orhigher. Any of the antioxidant components described herein may be usedin such methods.

The invention provides for the use of the described antioxidantcomponents in lubricating compositions, at the minimum required level,as a seal protectant, including lubricating compositions for industrialapplications. The invention provides even more specifically for windturbines and other applications that require fatigue or micro-pittingresistant formulations and even applications that have stringent sealcompatibility requirements.

The invention further provides for all of the compositions, methods, anduses described herein, where the specified lubricant includes ademulsifier, where the specified lubricant includes a combination of ademulsifier and a sulfurized olefin, where the specified lubricantincludes a combination of a substituted triazole and a substitutedthiadiazole, where the specified lubricant is essentially free of oreven completely free of dithiophosphates including zinc dialkyldithiophosphates, where the specified lubricant is essentially free ofor even completely free of overbased metal-containing detergents, wherethe specified lubricant is essentially free of or even completely freeof zinc, or any combination thereof.

DETAILED DESCRIPTION OF THE INVENTION

Various features and embodiments of the invention will be describedbelow by way of non-limiting illustration.

The invention provides an industrial lubricating composition comprisingan oil of lubricating viscosity and an antioxidant component comprising:(i) a phenolic antioxidant, (ii) an aminic antioxidant, or (iii) acombination thereof where the antioxidant component is present in thelubricating composition at 1.0 percent by weight or higher.

The Oil of Lubricating Viscosity

One component of the compositions of the invention is an oil oflubricating viscosity, which can be present in a major amount, for alubricant composition, or in a concentrate forming amount, for aconcentrate.

Suitable oils include natural and synthetic lubricating oils andmixtures thereof. In a fully formulated lubricant, the oil oflubricating viscosity is generally present in a major amount (i.e. anamount greater than 50 percent by weight). Typically, the oil oflubricating viscosity is present in an amount of 75 to 95 percent byweight, and often greater than 80 percent by weight of the overallcomposition. The base oil component generally makes up 100 parts byweight (pbw) of the overall composition with the pbw ranges for theother components being provided with this 100 pbw of base oil in mind.In other embodiments the pbw ranges of the various components, includingthe base oils, are provided such that the total of the pbw of allcomponents is 100, and thus the pbw values are equivalent to percent byweight values. The pbw ranges provided for the various componentsdescribed below may be taken either way, however in most embodimentsthey are to be read so as to be equivalent to percent by weight values.

The oil of lubricating viscosity may include natural and synthetic oils,oil derived from hydrocracking, hydrogenation, and hydrofinishing,unrefined, refined and refined oils or mixtures thereof. Unrefined oilsare those obtained directly from a natural or synthetic source generallywithout (or with little) further purification treatment. Refined oilsare similar to the unrefined oils except they have been further treatedin one or more purification steps to improve one or more properties.Purification techniques are known in the art and include solventextraction, secondary distillation, acid or base extraction, filtration,percolation and the like. Re-refined oils are also known as reclaimed orreprocessed oils, and are obtained by processes similar to those used toobtain refined oils and often are additionally processed by techniquesdirected to removal of spent additives and oil breakdown products.

Natural oils useful as the oil of lubricating viscosity include animaloils, vegetable oils (e.g., castor oil, lard oil), mineral lubricatingoils such as liquid petroleum oils and solvent-treated or acid-treatedmineral lubricating oils of the paraffinic, naphthenic or mixedparaffinic naphthenic types and oils derived from coal or shale ormixtures thereof.

Synthetic oils of lubricating viscosity include hydrocarbon oils such aspolymerized and interpolymerised olefins (e.g., polybutylenes,polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes),poly(1-octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls,alkylated polyphenyls); alkylated biphenyl ethers and alkylated biphenylsulfides and the derivatives, analogs and homologs thereof or mixturesthereof.

Another synthetic oil of lubricating viscosity includes polyol estersother than the hydrocarbyl-capped polyoxyalkylene polyol as disclosedherein, dicarboxylic esters, liquid esters of phosphorus-containingacids (e.g., tricresyl phosphate, trioctyl phosphate, and the diethylester of decane phosphonic acid), or polymeric tetrahydrofurans.Synthetic conventional oil of lubricating viscosity also include thoseproduced by Fischer-Tropsch reactions and typically may behydroisomerised Fischer-Tropsch hydrocarbons or waxes. In oneembodiment, the oil of lubricating viscosity may be prepared by aFischer-Tropsch gas-to-liquid synthetic procedure as well as othergas-to-liquid oils.

Oils of lubricating viscosity may further be defined as specified in theAmerican Petroleum Institute (API) Base Oil InterchangeabilityGuidelines. The five base oil groups are as follows: Group I (sulfurcontent ≧0.03 wt %, and/or <90 wt % saturates, viscosity index 80-120);Group II (sulfur content ≦0.03 wt % and ≧90 wt % saturates, viscosityindex 80-120); Group III (sulfur content ≦0.03 wt % and ≧90 wt %saturates, viscosity index ≧120); Group IV (all polyalphaolefins PAOssuch as PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8); and Group V. Theoil of lubricating viscosity includes API Group I, Group II, Group III,Group IV, Group V oil or mixtures thereof. In one embodiment, the oil oflubricating viscosity is an API Group I, Group II, Group III, Group IVoil or mixtures thereof. Alternatively, the oil of lubricating viscosityis often an API Group II, Group III or Group IV oil or mixtures thereof.

The various described oils of lubricating viscosity may be used alone orin combinations. The oil of lubricating viscosity is used in the rangeof about 70 wt % to about 99 wt %, and in another embodiment, in therange of about 75 wt % to about 98 wt %, in another embodiment in therange of about 88 wt % to about 97 wt % of the lubricant.

In some embodiments the lubricating oil component of the presentinvention includes a Group II or Group III base oil, or a combinationthereof. These are classifications established by the API (AmericanPetroleum Institute). Group III oils contain <0.03 percent sulfurand >90 percent saturates and have a viscosity index of >120. Group IIoils have a viscosity index of 80 to 120 and contain <0.03 percentsulfur and >90 percent saturates. The oil can also be derived from thehydroisomerization of wax, such as slack wax or a Fischer-Tropschsynthesized wax. Such “Gas-to-Liquid” oils are typically characterizedas Group III.

The compositions of the present invention may include some amount ofGroup I base oils, and even Group IV and Group V base oils.Polyalphaolefins are categorized as Group IV. Group V encompasses “allothers”. However, in some embodiments the lubricating oil component ofthe invention contains no more than 20, 10, 5, or even 1 percent byweight Group I base oil. These limits may also apply to Group IV orGroup V base oils. In other embodiments the lubricating oil present inthe compositions of the invention is at least 60, 70, 80, 90, or even 95percent by weight Group II and/or Group III base oil. In someembodiments the lubricating oil present in the compositions of theinvention is essentially only Group II and/or Group III base oil, wheresmall amounts of other types of base oils may be present but not inamounts that significantly impact the properties or performance of theoverall composition.

In some embodiments the compositions of the invention include someamount of Group I and/or Group II base oils. In other embodiments thecompositions of the invention are lubricating compositions where the oilof lubricating viscosity is primarily Group I and/or Group II base oils,or even essentially Group I and/or Group II base oils, or evenexclusively Group I and/or Group II base oils.

In some embodiments the compositions of the invention include someamount of Group I base oils. In other embodiments the compositions ofthe invention are lubricating compositions where the oil of lubricatingviscosity is primarily Group I base oils, or even essentially Group Ibase oils, or even exclusively Group I base oils.

In some embodiments the compositions of the invention include someamount of Group II base oils. In other embodiments the compositions ofthe invention are lubricating compositions where the oil of lubricatingviscosity is primarily Group II base oils, or even essentially Group IIbase oils, or even exclusively Group II base oils.

In some embodiment's the oil of lubricating viscosity may be present inthe range from 60 to 99.9, from 88.5 to 99.6, from 96.9 to 99.5, or from98.2 to 99.4 weight percent of the lubricating oil composition. Each oilof lubricating viscosity described above may be used alone or asmixtures of one or more thereof.

The Antioxidant Component

The present invention requires the described lubricant compositions toinclude a minimum level of a specific antioxidant component. Theantioxidant component includes: (i) a phenolic antioxidant, (ii) anaminic antioxidant, or (iii) a combination thereof. The antioxidantcomponent must be present in the described lubricating compositions at aminimum of 0.4, 0.5 or a minimum 1.0 percent by weight or higher.

Suitable phenolic antioxidants that may be used in the invention includesubstituted phenol that contains at least one alkyl substituent group.In some embodiments the phenolic antioxidant includes compounds free ofnitrogen which are also ashless. In some embodiments the phenolicantioxidant includes a substituted phenol containing at least twobranched alkyl substituent groups. In some embodiments the phenolicantioxidant comprises a substituted phenol containing at least twobranched alkyl substituent groups and further containing a estercontaining substituent group.

The phenolic antioxidant can include a sterically hindered phenols thatcontain an alkyl group ortho to the hydroxyl group, two alkyl groupsortho to the hydroxyl group that occupy the 2-position and 6-position ofthe phenolic ring, or a mixture thereof. The alkyl groups can contain 1to 24 carbon atoms and in other instances 3 to 18 and 3 to 12 carbonatoms. The alkyl groups can be linear, branched to include tertiaryalkyl groups, or a mixture thereof. The sterically hindered phenol canalso contain one or more additional alkyl groups and/or one or morehydrocarbyl groups such as a propionate ester group. Useful stericallyhindered phenols can include ortho-alkylated phenolic compounds such asfor example 2,6-ditertbutylphenol, 4-methyl-2,6-di-tertbutylphenol,2,4,6-tritertbutylphenol, 2-tert-butylphenol, 2,6-diisopropylphenol,2-methyl-6-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol,4-(N,N-dimethylaminomethyl)-2,6-di-tertbutyl phenol,4-ethyl-2,6-di-tertbutylphenol, and their analogs and homologs. Mixturesof two or more such mononuclear phenol compounds are also suitable.

In an embodiment of the invention the sterically hindered phenol can berepresented by the following formula:

wherein R⁴ is an alkyl group containing 1 up to 24 carbon atoms and a isan integer of 1 to 5. In some embodiments R⁴ contains 4 to 18 carbonatoms or even from 4 to 12 carbon atoms. R⁴ may be either straightchained or branched chained, and in some embodiments is branched. Thevalue for a can be 1 to 4, 1 to 3, or 2, or 3. In some embodiments thephenol is a butyl substituted phenol containing 2 or 3 t-butyl groups.In some embodiments one R4 group is located in the 4 position on thering and is hydrogen, a hydrocarbyl such as methyl, ethyl, or dodecyl.In any of these embodiments, when a is 2 and t-butyl groups occupy the2- and 6-positions of phenol, the phenol is extremely stericallyhindered and has the following structure:

In one embodiment of the invention the sterically hindered phenol can berepresented by the following formula:

wherein the t-alkyl groups can have 4 to 8 carbon atoms, and R³ is astraight chain or branched chain alkyl group containing 2 to 22, 2 to 8,2 to 6 carbon atoms or even just 4 carbon atoms. R³ is desirably a2-ethylhexyl group or an n-butyl group. Hindered, ester-substitutedphenols such as those of formula (III) can be prepared by heating a2,6-dialkylphenol with an acrylate ester under base catalysis conditionssuch as aqueous KOH as described in International Publication No.WO01/74978. In another embodiment of this invention the stericallyhindered phenol is an alkylation reaction product of an alkylphenol suchas a dodecylphenol and isobutylene to form a product containing adi-t-butylated alkylphenol. An embodiment of the invention is asterically hindered phenol having two or more alkyl substituents thatcontain 1 to 24 carbon atoms and that occupy the 2-position and6-position of the phenolic ring.

The phenolic antioxidant can also include an alkylene or alkylidenecoupled sterically hindered phenol oligomer. The coupled stericallyhindered phenol oligomer can contain two or more phenolic rings whereeach ring is occupied at the 2-, 4- and 6-positions by an alkyl groupsuch as a methyl or t-butyl group or an arylalkyl group such as a3,5-di-t-butyl-4-hydroxybenzyl group. The alkylene and alkylidenecoupling groups can be respectively methylene and ethylidene groups. Thealkyl groups can have 1 to 24 carbon atoms and in other instances canhave 3 to 18 and 3 to 12 carbon atoms. The alkyl groups can be linear,branched to include tertiary alkyl groups, or a mixture thereof. Thecoupled sterically hindered phenol oligomer can include a mixture of twoor more oligomers where each oligomer contains a different number ofphenolic rings. The coupling of the phenolic rings in an oligomer can beat ortho ring positions, at para ring positions, or at a mixture ofortho and para ring positions.

In an embodiment of the invention the phenolic antioxidant is a coupledalkylphenol which can be represented by the formula:

wherein each R⁵ is independently a tertiary alkyl group containing from4 to about 8 carbon atoms, each of X, Y and Z is independently hydrogenor a hydrocarbon radical, each R⁶ is independently an alkylene oralkylidene group, and n is a number ranging from zero to about 4. EachR⁵ group must be a tertiary alkyl group. Tertiary alkyl groups have thegeneral structure:

wherein each of J, K and L is an alkyl group of 1-4 carbon atoms.Representative tertiary alkyl groups are tertiary butyl, tertiary amyl,tertiary hexyl and tertiary octyl. The R⁵ groups may be the same ordifferent. In some embodiments all R⁵ are the same, and in still furtherembodiments are all tertiary butyl groups. Each R⁶ is independently adivalent group such as an alkylene or an alkylidene group. These groupsmay be substituted for example by various hydrocarbyl groups such asalkyl and aryl groups. Representative examples of suitable R⁶ groups aremethylene, ethylene, propylene, phenyl substituted methylene, methylsubstituted methylene, methyl substituted ethylene and the like.Typically, each R⁶ contains from one to about 10 carbon atoms, or fromone to about three carbon atoms. In one embodiment, R⁶ is phenylsubstituted methylene. In another embodiment, each is methylene, that isa group of the formula —CH₂—. Each X, Y and Z is independently hydrogenor a hydrocarbon-based group. These groups may be the same or different.In one embodiment, each of X, Y and Z is independently an aliphatichydrocarbon group. Thus each of these groups will contain at least onecarbon atom, but may contain more. In still further embodiments theycontain from 1 to about 500 carbon atoms, from 4 to about 100 carbonatoms, or even from about 4 to about 30 carbon atoms.

In an embodiment of the invention the phenolic antioxidant is amethylene coupled oligomer of a sterically hindered phenol such as forexample 4,4′-methylene-bis(6-tert-butyl-2-methylphenol),4,4′-methylene-bis(2-tert-amyl-6-methylphenol),2,2′-methylene-bis(4-methyl-6-tert-butylphenol),4,4′methylene-bis(2,6-di-tert-butylphenol), and similar compounds. In anembodiment of this invention a methylene coupled oligomer of asterically hindered phenol is2,2′-methylene-bis(6-tert-butyl-4-dodecylphenol) as described in U.S.Pat. No. 6,002,051 regarding its preparation and use.

Suitable aminic antioxidants that may be used in the invention includealkaryl amines and in some embodiments the aminic antioxidant is analkylphenyl amine. Suitable examples include a bis(4-alkylphenyl)amine.

The aminic antioxidant can include a secondary aromatic amine, typicallya monoamine, that contains one aryl group, two aryl groups, or a mixturethereof. An embodiment of the invention is a secondary aromatic aminecontaining one aryl group such as for example N-methylaniline. Thesecondary aromatic amine containing one aryl group can also have C₁-C₁₆alkyl or arylalkyl substituents on the aryl group. In another embodimentof the invention the secondary aromatic amine can be a diarylamine suchas for example diphenylamine, N-phenyl-1-naphthylamine or combinationsthereof. The diarylamine can contain one, two or more alkyl and/orarylalkyl substituents. The alkyl and arylalkyl substituents can have 1to 16 carbon atoms and in other instances can have 3 to 14 and 4 to 12carbon atoms. The alkyl and arylalkyl substituents can be linear,branched, or a mixture thereof. In an embodiment of the presentinvention the diarylamine is an alkylated diphenylamine which can berepresented by formula:

R⁷—C₆H₄—NH—C₆H₄—R⁸  (VI)

wherein R⁷ and R⁸ are independently a hydrogen or an alkyl groupcontaining 1 to 24 carbon atoms. The diphenylamine of formula (VI) canbe a mixture of diphenylamine and monoalkylated and dialkylateddiphenylamine. R⁷ and/or R⁸ can be alkyl groups containing from 4 to 20carbon atoms. In another embodiment of the invention the diphenylamineof formula (VI) is prepared by alkylating diphenylamine with nonenesusing well known alkylation methods. Alkylated diarylamines are alsocommercially available.

The antioxidant component must be present in the composition at least1.0 percent by weight. This treat rate is with respect to the finallubricant composition to be used in a mechanical device, but could alsobe applied to additive packages and concentrates which are then diluted,typically with oil, to produce the final lubricant. The weight percentdiscussed here are with respect to the overall lubricant composition.Any diluent that may be present in the antioxidant component isgenerally not considered when determining the percent by weight at whichthe antioxidant component is present in the composition. In addition,any materials in the antioxidant component other than the phenolic andaminic antioxidants described herein may be excluded when determiningthe percent by weight at which the antioxidant component is present inthe composition, such that the weight percent values discussed onlyapply to the phenolic and aminic antioxidants.

Also it is noted that in some embodiments the antioxidant componentincludes one or more phenolic antioxidants and no aminic antioxidants.In other embodiments the antioxidant component includes one or moreaminic antioxidants and no phenolic antioxidants. In still otherembodiments the antioxidant component includes a combination of one ormore aminic antioxidants and one or more phenolic antioxidants.

In some embodiments the phenolic antioxidant is present in thelubricating composition from at least 0.5 percent by weight and theaminic antioxidant is present in the lubricating composition from atleast 0.5 percent by weight. In some embodiments the phenolicantioxidant is present in the lubricating composition from at least 1.0percent by weight and the aminic antioxidant is present in thelubricating composition from at least 1.0 percent by weight or from 0.5percent by weight.

Additional Additives

Optionally the lubricating compositions of the invention include one ormore additional additives, which may be selected from the groupincluding: a foam inhibitor, a demulsifier, a pour point depressant, anantioxidant other than those described above, a dispersant, a metaldeactivator (such as a copper deactivator), an antiwear agent, extremepressure agent, viscosity modifiers, or mixtures thereof. The optionaladditives may each be present in the range from 0.0005 to 1.3, from0.00075 to 0.5, from 0.001 to 0.4, or from 0.0015 to 0.3 percent byweight of the lubricating oil composition. However it is noted that someoptional additives, including viscosity modifying polymers, which mayalternatively be considered as part of the base fluid, may be present inhigher amounts including up to 30, 40, or even 50% by weight whenconsidered separate from the base fluid. The optional additives may beused alone or mixtures thereof.

Antifoams, also known as foam inhibitors, are known in the art andinclude but are not limited to organic silicones and non-silicon foaminhibitors. Examples of organic silicones include dimethyl silicone andpolysiloxanes. Examples of non-silicon foam inhibitors include but arenot limited to polyethers, polyacrylates and mixtures thereof as well ascopolymers of ethyl acrylate, 2-ethylhexylacrylate, and optionally vinylacetate. In some embodiments the antifoam is a polyacrylate. Antifoamsmay be present in the composition from 0.001 to 0.012 or 0.004 pbw oreven 0.001 to 0.003.

Demulsifiers are known in the art and include but are not limited toderivatives of propylene oxide, ethylene oxide, polyoxyalkylenealcohols, alkyl amines, amino alcohols, diamines or polyamines reactedsequentially with ethylene oxide or substituted ethylene oxides ormixtures thereof. Examples of demulsifiers include polyethylene glycols,polyethylene oxides, polypropylene oxides, (ethylene oxide-propyleneoxide) polymers, including block copolymers of ethylene oxide andpropylene oxide, and mixtures thereof. In some embodiments thedemulsifiers is a polyether. Demulsifiers may be present in thecomposition from 0.002 to 0.012 pbw.

Pour point depressants are known in the art and include but are notlimited to esters of maleic anhydride-styrene copolymers,polymethacrylates; polyacrylates; polyacrylamides; condensation productsof haloparaffin waxes and aromatic compounds; vinyl carboxylatepolymers; and terpolymers of dialkyl fumarates, vinyl esters of fattyacids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehydecondensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor.Suitable rust inhibitors include hydrocarbyl amine salts ofalkylphosphoric acid, hydrocarbyl amine salts of dialkyldithiophosphoricacid, hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid, fattycarboxylic acids or esters thereof, an ester of a nitrogen-containingcarboxylic acid, an ammonium sulfonate, an imidazoline, mono-thiophosphate salts or esters, or any combination thereof; or mixturesthereof.

Suitable hydrocarbyl amine salts of alkylphosphoric acid of theinvention are represented by the following formulas:

wherein R²¹ and R²² are independently hydrogen, alkyl chains orhydrocarbyl, and in some embodiments at least one of R²¹ and R²² arehydrocarbyl. R²¹ and R²² contain about 4 to about 30, about 8 to about25, or even about 8 or 10 to about 20, or even from 13 to about 19carbon atoms. R²³, R²⁴ and R²⁵ are independently hydrogen, alkylbranched or linear alkyl chains with about 1 to about 30, in otherembodiments about 4 to about 24, or even from about 6 to about 20, andin some embodiments about 8 or 10 to about 16 carbon atoms. R²³, R²⁴ andR²⁵ are independently hydrogen, alkyl branched or linear alkyl chains,and in some embodiments at least one, or even two of R²³, R²⁴ and R²⁵are hydrogen, and further where at least one of R²³, R²⁴ and R²⁵ is ahydrocarbyl group containing at least 8 carbon atoms.

Examples of alkyl groups suitable for R²³, R²⁴ and R²⁵ include but arenot limited to butyl, sec butyl, isobutyl, tert-butyl, pentyl, n-hexyl,sec-hexyl, n-octyl, 2-ethyl, hexyl, ethyl-hexyl, decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl,octadecyl, octadecenyl, nonadecyl, eicosyl or mixtures thereof.

In one embodiment the hydrocarbyl amine salt of an alkylphosphoric acidis the reaction product of a C₁₄ to C₁₈ alkylated phosphoric acid withPrimene 81R (produced and sold by Rohm & Haas) which is a mixture of C₁₁to C₁₄ tertiary alkyl primary amines.

Hydrocarbyl amine salts of dialkyldithiophosphoric acid of the inventionused in the rust inhibitor package are represented by the formula:

wherein R²⁶ and R²⁷ are independently branched or linear alkyl groups.R²⁶ and R²⁷ contain about 3 to about 30, or from about 4 to about 25, orfrom about 5 to about 20, or even from about 6 to about 19 carbon atoms.R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid ofthe invention include but are not limited to the reaction product(s) ofdiheptyl or dioctyl or dinonyl dithiophosphoric acids withethylenediamine, morpholine or Primene 81R or mixtures thereof.

Suitable hydrocarbyl amine salts of hydrocarbyl arenesulphonic acidsused in the rust inhibitor package of the invention are represented bythe formula:

wherein Cy is a benzene or naphthalene ring. R²⁸ is a hydrocarbyl groupwith about 4 to about 30, or from about 6 to about 25, or from about 8to about 20 carbon atoms. z is independently 1, 2, 3, or 4 and in someembodiments z is 1 or 2. R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of hydrocarbyl arenesulphonic acidof the invention include but are not limited to the ethylenediamine saltof dinonylnaphthalene sulphonic acid.

Examples of suitable fatty carboxylic acids or esters thereof includeglycerol monooleate and oleic acid. An example of a suitable ester of anitrogen-containing carboxylic acid includes oleyl sarcosine.

The rust inhibitors may be present in the range from 0.02-0.2, from 0.03to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricatingoil composition. The rust inhibitors of the invention may be used aloneor in mixtures thereof.

The lubricating compositions of the invention may also include a metaldeactivator. Metal deactivators are used to neutralise the catalyticeffect of metal for promoting oxidation in lubricating oil. Suitablemetal deactivators include but are not limited to triazoles,tolyltriazoles, a thiadiazole, or combinations thereof, as well asderivatives thereof. Examples include derivatives of benzotriazoles,benzimidazole, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles,2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles,2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles,2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof. Theseadditives may be used from 0.01 to 0.25 percent by weight in the overallcomposition.

In some embodiments the metal deactivator is a hydrocarbyl substitutedbenzotriazole compound. The benzotriazole compounds with hydrocarbylsubstitutions include at least one of the following ring positions 1- or2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups containabout 1 to about 30, preferably about 1 to about 15, more preferablyabout 1 to about 7 carbon atoms, and most preferably the metaldeactivator is 5-methylbenzotriazole used alone or mixtures thereof.

The metal deactivators may be present in the range from 0.001 to 0.1,from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oilcomposition. Metal deactivators may also be present in the compositionfrom 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used aloneor mixtures thereof.

Antioxidants other than those described above may also be presentincluding a substituted hydrocarbyl mono-sulfide. In some embodimentsthe substituted hydrocarbyl monosulfides includen-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, orcombinations thereof. In some embodiments the substituted hydrocarbylmonosulfide is 1-(tert-dodecylthio)-2-propanol.

Dispersants may also be present including: (i) a polyetheramine; (ii) aborated succinimide dispersant; (iii) a non-borated succinimidedispersant; (iv) a Mannich reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof. In some embodiments the dispersant component is present from0.05 to 0.5 pbw of the overall composition.

The invention further provides for all of the compositions, methods, anduses described herein, where the specified lubricant includes ademulsifier, where the specified lubricant includes a combination of ademulsifier and a sulfurized olefin, where the specified lubricantincludes a highly sulfurized olefin such as a sulfurized olefincontaining at least 20% by weight sulfur, where the specified lubricantis essentially free or to even completely free of non-highly sulfurizedolefins such as a sulfurized olefin containing less than 20% by weightsulfur, where the specified lubricant includes a combination of asubstituted triazole and a substituted thiadiazole, where the specifiedlubricant is essentially free of or even completely free of metaldialkyl dithiophosphates, where the specified lubricant is essentiallyfree of or even completely free of overbased metal-containingdetergents, where the specified lubricant is essentially free of or evencompletely free of zinc, or any combination thereof.

INDUSTRIAL APPLICATION

The invention provides a process for the preparation of lubricating oilcompositions. The lubricating oil compositions are prepared by the stepscomprising: a) mixing and/or dissolving in one another the componentsdescribed above that includes the combination of an oil of lubricatingviscosity, the substituted triazole and optionally one more additionadditives. The materials are mixed until the additives are substantiallyor wholly dissolved, in some embodiments at elevated temperatures in therange 40° C. to 110° C., or 50° C. to 95° C., or even 55° C. to 85° C.;and for a period of time in the range 30 seconds to 24 hours, 2 minutesto 8 hours, or 5 minutes to 4 hours; and at pressures in the range 700mm of Hg to 2000 mm of Hg, 750 mm of Hg to 900 mm of Hg, or 755 mm of Hgto 800 mm of Hg.

The order of addition of the additives is not overly limited. Theoptional additives may be mixed in at the same time as the othercomponents or at a later time using any of the mixing proceduresdescribed above.

In some embodiments a portion of oil or similar diluent is present withthe components and the components are mixed into the oil. In otherembodiments a minimal amount of oil or diluent is present, other thanthat amount inherently present in the additive from their means ofproduction and preparation and additional base oil is added after thecomponent have been mixed. In any event the described processes resultsin lubricating compositions.

In some embodiments the lubricating oil compositions may be preparedfrom a concentrate comprising the steps of: a) mixing all of thecomponents described above with minimal oil and/or diluent present,other than optionally some relatively small amount to allow forreasonable handling properties. The resulting concentrate may then beused in the preparation of a lubricating composition by mixing theconcentrate with an effective amount of base oil or mixtures thereofresulting in a finished fluid. Optional additives may be added to theconcentrate or to the resulting final fluid. These optional additivesinclude any of those described above. In some embodiments these optionaladditives include a foam inhibitor, a demulsifier, a viscosity modifier,a pour point depressant, or mixtures thereof, and may be added such thatthey are present in the overall compositions in the range about 0, 0.01,0.1 or even 0.25 or up to about 13, 10, 8 or even 6 pbw.

In some embodiments the compositions of the invention have an ISOviscosity grade from 100 to 1000, or from 100 to 460, or even from 100or 150 to 320. In some embodiments the compositions of this inventionare not grease compositions or engine oil compositions. Rather thesecompositions can be industrial gear oils, wind turbine lubricants,bearing lubricants, and the like, and in some embodiments evenautomotive gear oils.

Specific Embodiment

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

The example sets below are designed to evaluate and compare thefollowing additives: Antioxidant A, an alkylated phenol; and AntioxidantB, an alkaryl amine.

To evaluate the additives, the examples in the example sets below aretested to evaluate their seal compatibility. Using NBR 902 seals thesamples are tested for approval under the Flender-Siemens specification(F-S) for wind turbines, which involves 1000 hours of testing at 130° C.for each sample. Under this specification, ideally the fluid must giveresults including a hardness change of not more than 5 points (−5 to+5), a percent volume change from a 2% decrease to a 5% increase (−2% to+5%), a percent tensile decrease of no more than 60% (−60% max) and apercent elongation decrease of no more than 60% (−60% max). Thesespecifications, in particular the Flender-Siemens specification, arevery hard to meet, and a relative improvement in performance over aconventional comparative example, even if not a clean pass, would stillbe considered to be a significant improvement. In fact, a sample thatmeets the specification expect for having a hardness change up to +7, avolume change up to +6%, or a elongation change of down to −65% is stillconsidered to have met the a specification and passed the test, so longas only one of these areas is outside the normal pass range. Thissecondary allowance for one of the ratings allows for a passing resulteven if the sample did not show a “clean pass” with all ratings insidethe ideal ranges.

However, as is evident from the results, it is important to considerrelative performance of the examples rather than just the pass failresult. When considering the Flender-Siemens specification (F-S) resultsof the example sets and comparing the relative performance it can behelpful to consider the degree to which a sample passed or failed. Thefollowing key can be used for this purpose with the best result at thetop of the table and the worst result at the bottom:

Result Key for Relative Performance Comparisons

Degree Rating Description of the Rating A PASS Clean Pass, no ratingsoutside the ideal ranges. B PASS Pass, one rating outside the idealrange but within the secondary allowance, discussed in the descriptionof the test method above. F1 1^(st) Degree Fail, the sample failed forhaving two ratings outside the ideal ranges but both within thesecondary allowances. F2 2^(nd) Degree Fail, the sample failed forhaving one rating outside both the ideal range and the secondaryallowances for that rating. F3 3^(rd) Degree Fail, the sample failed forhaving one rating outside both the ideal range and the secondaryallowances for that rating and also having another rating outside theideal ranges but within the secondary allowances. F4 4^(th) Degree Fail,the sample failed for having two ratings outside the both ideal rangeand the secondary allowances for those ratings. F5 5^(th) Degree Fail,the sample failed for having two ratings outside both the ideal rangeand the secondary allowances for those ratings and also having a thirdrating outside the ideal ranges but within the secondary allowances. F66^(th) Degree Fail, the sample failed for having three ratings outsidethe both ideal range and the secondary allowances for those ratings andalso having a third rating outside the ideal ranges but within thesecondary allowances.

Example Set 1

A set of examples is prepared in a Group I (GI) base oil. Each of theexamples contains the same conventional additives package in the sameamount, such that the sample is suitable for use as a lubricant inindustrial gear applications. Each sample is top-treated with one of theantioxidant described above to see the impact the added materials haveon the formulation's performance, specifically in regards to sealcompatibility.

The conventional additive package used in each of these examples, isreferred to as Additive Package A and contains a metal deactivator, ademulsifier, a rust inhibitor, a mixture of antiwear and extremepressure agents, an antifoam agent, a detergent, and a corrosioninhibitor. None of the additives in Additive Package A meet therequirements for the antioxidant component of the invention.

The samples are tested to evaluate their seal compatibility using thesame test method described above. The results from the testing ofExample Set 1 are summarized in the table below:

TABLE 1 Summary of Results from Example Set 1 Ex Ex Ex Ex Ex Ex Ex Ex ExEx Ex Ex 1-1¹ 1-2 1-3 1-4 1-5¹ 1-6 1-7¹ 1-8 1-9¹ 1-10 1-11 1-12 Ex Typecomp comp comp comp comp comp comp inv comp inv inv inv Base Oil² GI GIGI GI GI GI GI GI GI GI GI GI Add Pack A A A A A A A A A A A AAntioxidant A 0.2 0.2 0.5 0.5 1.0 1.0 Antioxidant B 0.2 0.2 0.5 0.5 1.01.0 F-S Spec F4 F3 F1 F1 F4 F4 F3 B F4 A A A PASS PASS PASS PASSHardness Δ 8 7 7 6 9 8 8 6 8 5 4 4 % Vol Δ 2 2 2 2 2 3 3 3 2 3 3 4 %Tensile Δ −3 0 −2 −4 11 −4 −1 −1 −3 −3 −2 −4 % Elong Δ −72 −71 −65 −68−74 −71 −64 −59 −72 −55 −55 −58 ¹Examples 1-1, 1-5 and 1-9 are repeatsof the baselines which was re-tested for each set of samples atdifferent treat levels. These examples provide good baseline comparisonswhile also showing the repeatability of the test. ²The base oil used inthese examples is an API Group I base oil.

The results show that the inventive examples provide improved sealcompatibility in Group I based formulations over the comparativeexamples.

Example Set 2

A set of examples is prepared in a Group II (GII) base oil. Each of theexamples contains the same conventional additives package describedabove in Example Set 1. The samples are tested to evaluate their sealcompatibility using the same test methods described above. The resultsfrom the testing of Example Set 2 are summarized in the table below:

TABLE 2 Summary of Results from Example Set 2 Ex Ex Ex Ex Ex Ex Ex Ex2-1¹ 2-2 2-3 2-4 2-5¹ 2-6 2-7¹ 2-8 Ex Type comp comp comp inv comp invinv inv Base Oil² GII GII GII GII GII GII GII GII Add Pack A A A A A A AA Antioxidant A 0.5 0.5 1.0 1.0 Antioxidant B 0.5 0.5 1.0 1.0 F-S SpecF4 F4 F3 F3 F4 F4 F3 F3 Hardness Δ 8 8 7 6 8 8 6 6 % Vol Δ 2 2 2 3 2 2 44 % Tensile Δ 11 6 8 2 6 5 3 2 % Elong Δ −74 −79 −71 −76 −76 −76 −67 −67¹Examples 2-1 and 2-5 are repeats of the baselines which was re-testedfor each set of samples at different treat levels. These examplesprovide good baseline comparisons while also showing the repeatabilityof the test. ²The base oil used in these examples is an API Group IIbase oil.

The results show that the inventive examples provide improved sealcompatibility in Group II based formulations. However, as is evidentfrom the results, here it is important to consider relative performanceof the examples rather than just the pass fail result.

While the invention has been explained, it is to be understood thatvarious modifications thereof will become apparent to those skilled inthe art upon reading the specification. Therefore, it is to beunderstood that the invention disclosed herein is intended to cover suchmodifications as fall within the scope of the appended claims.

In this specification the terms “hydrocarbyl substituent” or“hydrocarbyl group,” as used herein are used in their ordinary sense,which is well-known to those skilled in the art. Specifically, theyrefer to a group primarily composed of carbon and hydrogen atoms that isattached to the remainder of the molecule through a carbon atom and doesnot exclude the presence of other atoms or groups in a proportioninsufficient to detract from the molecule having a predominantlyhydrocarbon character. In general, no more than two, preferably no morethan one, non-hydrocarbon substituent will be present for every tencarbon atoms in the hydrocarbyl group; typically, there will be nonon-hydrocarbon substituents in the hydrocarbyl group. A more detaileddefinition of the terms “hydrocarbyl substituent” or “hydrocarbylgroup,” is described in U.S. Pat. No. 6,583,092.

Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, all percent and formulation valueslisted herein are on a weight basis. Unless otherwise indicated, eachchemical or composition referred to herein should be interpreted asbeing a commercial grade material which may contain the isomers,by-products, derivatives, and other such materials which are normallyunderstood to be present in the commercial grade. However, the amount ofeach chemical component is presented exclusive of any solvent ordiluent, which may be customarily present in the commercial material,unless otherwise indicated. It is to be understood that the upper andlower amount, range, and ratio limits set forth herein may beindependently combined. Similarly, the ranges and amounts for eachelement of the invention can be used together with ranges or amounts forany of the other elements. As used herein, the expression “consistingessentially of” permits the inclusion of substances that do notmaterially affect the basic and novel characteristics of the compositionunder consideration.

We claim:
 1. An industrial lubricating composition comprising an oil oflubricating viscosity and an antioxidant component comprising: (i) aphenolic antioxidant, (ii) an aminic antioxidant, or (iii) a combinationthereof; wherein the antioxidant component is present in the lubricatingcomposition at 1.0 percent by weight or higher.
 2. The composition ofclaim 1 wherein the phenolic antioxidant is present in the lubricatingcomposition from at least 0.5 percent by weight; and wherein the aminicantioxidant is present in the lubricating composition from at least 0.5percent by weight.
 3. The composition of claim 1 wherein the phenolicantioxidant comprises a substituted phenol containing at least one alkylsubstituent group.
 4. The composition of claim 1 wherein the aminicantioxidant comprises a diarylamine.
 5. The composition of claim 1wherein the oil of lubricating viscosity comprises a mineral base oil.6. The composition of claim 1 wherein the oil of lubricating viscositycomprises a synthetic base oil.
 7. The composition of claim 1 furthercomprising: an antiwear agent, an extreme pressure agent, a frictionmodifier, a corrosion inhibitor, a rust inhibitor, a metal deactivator,a borated dispersant, a non-borated dispersant, detergent, an antifoam,a viscosity index improver, a viscosity modifier, an antioxidant, a pourpoint depressant, a seal swell agent, or any combination thereof.
 8. Amethod of lubricating an industrial gear assembly comprising supplyingto said assembly a lubricating composition comprising an oil oflubricating viscosity and an antioxidant component comprising: (i) aphenolic antioxidant, (ii) an aminic antioxidant, or (iii) a combinationthereof; wherein the antioxidant component is present in the lubricatingcomposition at 1.0 percent by weight or higher.
 9. The method of claim 8wherein the phenolic antioxidant is present in the lubricatingcomposition from at least 0.5 percent by weight; and wherein the aminicantioxidant. antioxidant is present in the lubricating composition fromat least 0.5 percent by weight.
 10. The method of claim 8 wherein thephenolic antioxidant comprises a substituted phenol containing at leastone alkyl substituent group.
 11. The method of claim 8 wherein theaminic antioxidant comprises a diarylamine.
 12. The method of claim 8wherein the oil of lubricating viscosity comprises a mineral base oil.13. The method of claim 8 wherein the oil of lubricating viscositycomprises a synthetic base oil.
 14. The method of claim 8 wherein thelubricating composition further comprising: an antiwear agent, anextreme pressure agent, a friction modifier, a corrosion inhibitor, arust inhibitor, a metal deactivator, a borated dispersant, a non-borateddispersant, detergent, an antifoam, a viscosity index improver, aviscosity modifier, an additional antioxidant, a pour point depressant,a seal swell agent, or any combination thereof.
 15. A method ofimproving the seal compatibility of an industrial gear assemblylubricant comprising adding to said lubricant composition an antioxidantcomponent comprising: (i) a phenolic antioxidant, (ii) an aminicantioxidant, or (iii) a combination thereof; wherein the antioxidantcomponent is present in the lubricant at 1.0 percent by weight orhigher.
 16. (canceled)